1. Field of the Invention
The present invention relates to a method of spraying additives, in an intensively mixing manner, i.e. at high mixing energy, into a combustion chamber for capturing or binding sulfur during the combustion of fuels which contain sulfur.
2. Description of the Prior Art
Methods for mixing additives, which bind sulfur-containing impurities, into the combustion gases during the combustion of sulfur-containing fuels are known, according to which the additives are introduced into the combustion chamber in various ways.
Pursuant to one known method, "Fortschrittsberichte, VDI-Zeitschrift" (Progress Reports, Journal of the Association of German Engineers), Series 6, Number 21, August 1968, the process includes spraying the additives in the form of white calcium hydroxide and dolomite calcium hydroxide into the combustion chamber, above the region of the flame, with the aid of air jets. The drawback of this known method is that the manner in which the additives are introduced into the combustion chamber does not assure binding of the sulfur by the additives for the reason that the relatively low mixing energy of the air jets is not sufficient for achieving a good mixing intensity of the reaction constituents. Furthermore, the mixing of the reaction constituents is effected for the most part in temperature ranges which do not assure optimum reaction conditions.
Pursuant to a further known method of the aforementioned general type (U.S. Pat. No. 4,331,638 Michaelfelder dated May 25, 1982, which belongs to the assignee of the present invention), pulverous additives, such as the oxides and hydroxides of the metals sodium, potassium, aluminum, calcium, and others, are added from the wall of the burner by means of a gaseous and/or liquid carrier-medium stream, accompanied by the formation of a veil which surrounds the flame of the burner. The drawback of this known method is that the manner of introducing the additive into the combustion chamber again does not assure the binding of the sulfur by the additives, in this case because adding the additives into the region of the flame, from the burner wall, results in a large portion of the additive quantity passing through that flame region having the highest temperatures, which prevents binding of the sulfur. This drawback is particularly serious during the combustion of liquid and/or gaseous fuels due to the intensive, high-temperature flames. A further drawback is that the possible injection locations for the additives are limited by the type of injection to those regions from which the intensive mixing regions of the flame can be reached.
An object of the present invention is to develop a method of the aforementioned general type for use with binding sulfur, which assures that during the addition of sulfur-binding additives, the latter are combined with the combustion gases in such a way that an intensive mixing is achieved in that temperature range which is optimum for the binding reactions.